The article considers those aspects of the development of sociological knowledge in Russia that were determined by the scientific and organizational activities of A.S. Lappo-Danilevsky (1863-1919). His contribution to the development of the Russian social and humanitarian thought is associated mainly with the development of the foundations of history, historiography and source studies, which is widely admitted in scientific works. However, Lappo-Danilevsky's contribution to the development of sociology, to the identification of the specifics of its subject and to the creation of a model of systemic courses on the historical reconstruction of sociological knowledge are still widely discussed. The authors consider the creative component of Lappo-Danilevsky's legacy and the strategy he developed for creating an interdisciplinary methodology for social sciences. The article aims at describing his contribution to the institutionalization of Russian sociology, which allows not only to clarify the origins of social knowledge in Russia, but also to actualize Lappo-Danilevsky's legacy. The authors pose new questions and problematize the research potential of the works of Russian scientists at the turn of the 20th century, which has prospects for supplementing the history and methodology of sociology. The description of the activities of Lappo-Danilevsky - from the development of the institutional foundations of Russian sociology to the clarification of the methodological principles of social knowledge - raises the question of the influence of positivism and neo-Kantianism on the scientific community On the other hand, the study of the scientific and organizational activities of Lappo-Danilevsky allow to expand the field of history and methodology of sociology by supplementing it with a description of the institutionalization of sociology in Russia. The study of the foundations of sociological knowledge emphasizes three points: creation of methodology, separation from related disciplines, and acceptance of the historical component in the development of academic sociology. The article also mentions contemporary discussions which consider the sociological legacy of Lappo-Danilevsky not only as a historical reconstruction of the development of social knowledge, but also in the interdisciplinary perspective of contemporary sociology.